Nuclear power plants generate spent nuclear fuels (SNF). SNF typically contains uranium, and other radioactive actinide elements such as neptunium, plutonium, americium and curium, radioactive rare earth elements, the radioactive transition metal technetium, as well as radioactive cesium and strontium.
The spent nuclear fuel may be in the form of a fuel kernel or particle and may include a coating, such as a TRISO-coated particle fuel or a TRIZO-coated particle fuel. TRISO is an acronym for TRI-structural, ISOtropic, with the coatings being a buffer, such as low-density pyrolytic carbon, high density pyrolytic carbon (IPyC and OPyC), and silicon carbide (SiC). TRIZO-coated particle fuel is similar to the TRISO-coated particle fuel and includes a thin layer of Zirconium (ZrC) deposited on the kernel and/or in the buffer layer. The coating serves as a miniature pressure vessel that provides containment of radionuclides and gases.
The spent nuclear fuel may be processed to separate reusable transuranics and uranium from the fission products. The TRIZO-coated fuels contain Zirconium (Zr) in the fuel kernel coatings. Zirconium may contaminate the uranium and technetium or the transuranics separated from the TRIZO-coated fuels during processing.